1. Ultra-Stable Lasers Supervisor Dr Randy Bartels Team Members Steven Dorlac, Andrew Wiersma, Daxsamuel Chitechi, Derrick Bernallie

2. Ultra-Stable Lasers Project Overview Develop an Optically-Based Clock – Ultra-Stable External Cavity Diode Laser (ECDL) Stable Optical Frequency Comb (image shown on right) Driving/Stabilizing Electronics – Applications Precision Clocks Telecommunications Precision Navigation Source: Encyclopedia of Laser Physics and Technology (website)

3. Ultra-Stable Lasers ECDL System Overview Key Components – External Cavity Diode Laser – Thermoelectric Control (TEC) – Power Supply (PSU) – Piezo-Electric Power Supply (PZT PS) – Diode Driver – Loop Control/Filter – Optics Current Controller

4. Ultra-Stable Lasers Semester Goals and Assignments Develop ECDL electronics – Diode Driver: Andy Wiersma – TEC: Dax Chitechi – Power Supply: Derrick Benallie – Control/Filter: Steven Dorlac

5. Current Controller Supplies a very low noise current to the LASER diode Typical Inputs – Power Supply Supplies power to the Current Driver to produce a current – Servo Circuit Provides feedback to the Current Driver to compensate for changes Typical Outputs – Laser Diode Supplies Current to the Diode

6. Current Controller Overview

7. Current Controller Key Parts 1)Supply Source 2)Circuit Feedback 3)Current Line 4)Output to Diode

8. Thermoelectric Controller TEC Maintain the ECDL at constant temperature. Typical inputs: – Thermistor & thermocouple Typical outputs: – Peltier cooler & heater

9. Thermoelectric controller overview

10. Thermoelectic Controller Key Parts 1)Low power low cost 2.5V reference 2)Gain stage 3)Peltier cooling and heating stage

11. Power Supply PSU Supplies Power other Circuits – General power TEC PZT PS Current Controller Cost effective to simply purchase

12. Pulsed Power Supply PZT PS Supplies Power to the PZT Driver – Provides high voltage supply to supply to PZT Piezoelectric Disc – Mounted to back of optical mirrors – Changes Cavity Length Changes output freqency

13. Pulsed Power Supply

14. More efficient Carefully designed not to have high power peaks

15. Control/Filter Electronics Control Stabilizes ECDL Frequency Can be cascaded Typical Inputs – Photodetector Typical Outputs – Piezo Disc Adjusts External Cavity – Diode Driver Adjusts Current to Diode

16. Control/Filter Electronics Key Components

17. Budget 1)Current Controller Parts: $138.43 2)Thermoelectric Cooling Parts: $76.15 3)Power Supply Parts: $133.77 4)Loop Electronics Parts: $109.31 -Total for parts so far:$457.67 -Amount coming in from senior design: $350 -We plan on getting the rest of our funding from Prof. Bartels for the PCB and any extra costs we come across -PCB: ~$50 for each circuit= $200 -One major expense we still have other than the PCB is two EMCO model G03 which we are currently looking for more affordable alternative replacement parts

18. Review ECDL Circuits – Connections – Purpose – Features Current Controller

19. Next Semester Plans/Goals Design, Integrate and Build ECDL components – Diode Housing, External Cavity, Mirrors, Gratings, Piezo Discs, Photodetector Assemble ECDL system – Attach electronics – Setup and calibration of electronics Achieve stable optical comb output from ECDL

20. Thanks for Listening Any Questions?